We will be investigating: 1) The peptide-containing nerves of the kidney. Immunocytochemical methods will be used and substance P, somatostatin, enkephalin and vasoactive intestinal polypeptides will be investigated initially. Investigation of other peptides will follow. The relationship of the peptide-containing nerves with the monoaminergic innervation will be done by combining immunocytochemical with autoradiographic methods. 2) Neuroeffector junctions in various portions of the tubule will be investigated by lifting light micrscopic autoradiograms for ultramicrotomy and electron microscopy. 3) The macula densa using immunocytochemical methods for Tamm-Horsfall protein and morphometric methods. The long term objectives of this study are the investigation of the functional anatomy of the renal nerves and the JGA. This investigation holds relevance in regard to body fluid homeostasis and possibly in the development of hypertension.